Light olefin oligomerization is a process that can perform the conversion of C4 and C5 olefins into more desirable products. More specifically, it can convert light olefins into a diesel range product, or distillate. However, depending on the catalyst, the product from the oligomerization may have very poor diesel quality. For example, the olefinic distillate made by oligomerization process using an amorphous silico alumina (“ASA”) catalyst typically has a very low cetane number (i.e., around 30 or less).
Other catalyst types have been utilized to convert C4 and C5 olefins into an olefinic distillate product having a desirable or target cetane number. The olefinic distillate product, which may also be hydrotreated, is a liquid fuel which can be directly used for diesel blending component. One such catalyst that has been more recently suggested for use in light olefin oligomerization is the MTT catalyst. However, while the MTT catalyst can perform the oligomerization reaction, deactivation must be counteracted.
Accordingly, there is an ongoing need or desire to provide processes for converting C4 and C5 olefins into an olefinic distillate product which address or counteract the deactivation of the catalyst from coke formation, impurities, and contaminants while still achieving a target distillate yield with a target product quality.